<PAGE> PAGE 1
000 A000000 09/30/97
000 C000000 781880
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0
000 J000000 U
001 A000000 LEGG MASON SPECIAL INVESTMENT TRUST, INC.
001 B000000 811-4451
001 C000000 4105390000
002 A000000 111 SOUTH CALVERT STREET
002 B000000 BALTIMORE
002 C000000 MD
002 D010000 21202
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 N
007 B000000 0
062 A000000 N
062 B000000 0.0
062 C000000 0.0
062 D000000 0.0
062 E000000 0.0
062 F000000 0.0
062 G000000 0.0
062 H000000 0.0
062 I000000 0.0
062 J000000 0.0
062 K000000 0.0
062 L000000 0.0
062 M000000 0.0
062 N000000 0.0
062 O000000 0.0
062 P000000 0.0
062 Q000000 0.0
062 R000000 0.0
071 A000000 167836
071 B000000 117721
071 C000000 1156899
071 D000000 10
072 A000000 6
072 B000000 930
072 C000000 3763
072 D000000 0
072 E000000 0
072 F000000 4540
072 G000000 0
<PAGE> PAGE 2
072 H000000 0
072 I000000 425
072 J000000 131
072 K000000 74
072 L000000 40
072 M000000 6
072 N000000 52
072 O000000 0
072 P000000 0
072 Q000000 0
072 R000000 15
072 S000000 21
072 T000000 5773
072 U000000 0
072 V000000 0
072 W000000 24
072 X000000 11101
074 N000000 1444137
074 T000000 1432166
075 A000000 0
075 B000000 1200888
077 A000000 N
SIGNATURE MARIE K. KARPINSKI
TITLE TREASURER
WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000781880
<NAME> LEGG MASON SPECIAL INVESTMENT TRUST, INC. - PRIMARY SHARES
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-START> APR-01-1997
<PERIOD-END> SEP-30-1997
<INVESTMENTS-AT-COST> 862102
<INVESTMENTS-AT-VALUE> 1438137
<RECEIVABLES> 5963
<ASSETS-OTHER> 37
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 1444137
<PAYABLE-FOR-SECURITIES> 8905
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3066
<TOTAL-LIABILITIES> 11971
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 809896
<SHARES-COMMON-STOCK> 40657
<SHARES-COMMON-PRIOR> 35689
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> (6390)
<ACCUMULATED-NET-GAINS> 16693
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 576035
<NET-ASSETS> 1432166
<DIVIDEND-INCOME> 3763
<INTEREST-INCOME> 930
<OTHER-INCOME> 0
<EXPENSES-NET> 11080
<NET-INVESTMENT-INCOME> (6387)
<REALIZED-GAINS-CURRENT> 16945
<APPREC-INCREASE-CURRENT> 330112
<NET-CHANGE-FROM-OPS> 340670
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 48210
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 7070
<NUMBER-OF-SHARES-REDEEMED> (3813)
<SHARES-REINVESTED> 1711
<NET-CHANGE-IN-ASSETS> 443067
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 50048
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 4540
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 11101
<AVERAGE-NET-ASSETS> 1151489
<PER-SHARE-NAV-BEGIN> 26.55
<PER-SHARE-NII> (.16)
<PER-SHARE-GAIN-APPREC> 8.74
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> (1.33)
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 33.80
<EXPENSE-RATIO> 1.84
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000781880
<NAME> NAVIGATOR SPECIAL INVESTMENT TRUST
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-START> APR-01-1997
<PERIOD-END> SEP-30-1997
<INVESTMENTS-AT-COST> 862102
<INVESTMENTS-AT-VALUE> 1438137
<RECEIVABLES> 5963
<ASSETS-OTHER> 37
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 1444137
<PAYABLE-FOR-SECURITIES> 8905
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3066
<TOTAL-LIABILITIES> 11971
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 35932
<SHARES-COMMON-STOCK> 1671
<SHARES-COMMON-PRIOR> 1531
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> (6390)
<ACCUMULATED-NET-GAINS> 16693
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 576035
<NET-ASSETS> 1432166
<DIVIDEND-INCOME> 3763
<INTEREST-INCOME> 930
<OTHER-INCOME> 0
<EXPENSES-NET> 11080
<NET-INVESTMENT-INCOME> (6387)
<REALIZED-GAINS-CURRENT> 16945
<APPREC-INCREASE-CURRENT> 330112
<NET-CHANGE-FROM-OPS> 340670
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 2090
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 474
<NUMBER-OF-SHARES-REDEEMED> (406)
<SHARES-REINVESTED> 72
<NET-CHANGE-IN-ASSETS> 443067
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 50048
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 4540
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 11101
<AVERAGE-NET-ASSETS> 49399
<PER-SHARE-NAV-BEGIN> 27.04
<PER-SHARE-NII> (.01)
<PER-SHARE-GAIN-APPREC> 8.95
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> (1.33)
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 34.65
<EXPENSE-RATIO> .82
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
